Null modeming is really very easy.
Go to radio shack and buy a Null modem.
Its just a little Thingie thats looks like a cable
gender changer. Plug the serial cables from each
machine togather using the null modem as a
connector. The null modem inverts 2 wires so
that when you connect them the outgoing signal
goes to the incoming on the other and vise-versa.
You need to run a terminal program on each machine. They talk to each other through the terminal prgs. I've used it many , many times when
I was running a BBS on a clone for the Amigas.
Hope this helps.
Mel Ott